Logic-memory device of a mechanical resonator

Abstract

We report multifunctional operation based on the nonlinear dynamics in a single microelectromechanical system (MEMS) resonator. This Letter focuses on a logic-memory device that uses a closed loop control and a nonlinear MEMS resonator in which multiple states coexist. To obtain both logic and memory operations in a MEMS resonator, we examine the nonlinear dynamics with and without control input. Based on both experiments and numerical simulations, we develop a novel device that combines an OR gate and memory functions in a single MEMS resonator.PACS numbers: 85.85.+j, 05.45.-a, 62.40.+i, 45.80.+r, Microelectromechanical systems or nanoelectromechanical systems (MEMS or NEMS) resonators have been developed for use as filters, frequency references, and sensor elements [1]. Recently, significant research has focused on mechanical computation based on MEMS or NEMS resonators [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Some studies have shown that a single mechanical resonator can be used as a mechanical 1-bit memory [2,3,5,7,8,[11][12][13]15] or as mechanical logic gates [6,9,10]. Recently, multifunctional operation has been demonstrated in the form of a shift-register and a controlled NOT gate made from a single mechanical resonator [17]. The next phase is to use a closed loop control to generate multifunction devices, which consist of memory and multiple-input gates, in a single device. The closed loop allows output and excitation signals to be fixed at a single frequency. The goal of the work presented in this Letter is to develop multifunction operation from a nonlinear MEMS resonator in which multiple states coexist with closed loop control.Nonlinear dynamical responses are commonly observed in a MEMS resonator. The nonlinear dynamics of the MEMS resonator is well known to be described by the Duffing equation [2,8,12,[18][19][20]. Such a nonlinear MEMS resonator has hysteretic characteristics, which lead to two stable states and one unstable state, depending on the frequency [1,21] or excitation force [6,15].This Letter focuses on fabricating a multifunction device that offers logic and memory (called a "logic-memory device"). To do this, we examine the nonlinear dynamics in a MEMS resonator with and without control input. In the following, we discuss the experiments and numerical simulations that allowed us to develop a device that combines multiple-input gate and memory functions in a single nonlinear MEMS resonator.The proposed comb-drive MEMS resonator is shown in Fig. 1. The resonator consists of a perforated mass with a width, length, and thickness of 175, 575, and 25 µm, respectively [19,22,23]. When the comb-drive resonator is electrically excited, the mass vibrates in the lateral direction. The vibration of the mass is detected by using a differential measurement [24] in vacuum (around 10 Pa) at room temperature. The output voltage of the differential measurement is V out ∝ v ac A e sin(2ω e t + φ e ), where A e denotes the displacement amplitude and φ e is the phase. The vibration di...

A micro resonant charge sensor with enhanced sensitivity based on differential sensing scheme and leverage mechanisms

“…This result is due to the mechanical nonlinearity named spring hardening which is associated with the impact of mechanical restoring force. 18,19 Both the resonators show a similar trend of electrical and mechanical nonlinearity which can be mutually canceled since the device works in the differential sensing scheme. Therefore, the defects of nonlinear behavior such as energy dissipation and resonance instability can be suppressed.…”

Time-Resolved Nonlinear Coupling between Orthogonal Flexural Modes of a Pristine GaAs Nanowire

“…The hysteresis due to the nonlinearity of the modes also provides a straightforward way to store these logical output states. 10,11 In conclusion, we have shown that two orthogonal flexural modes of a GaAs nanowire can couple through nonlinear terms in the motion. The mode coupling is clearly visible in ringdown measurements, where we observe a beating pattern with frequency equal to the difference in mode frequencies.…”

“…7 Furthermore, the coupling of mechanical modes has various applications including in frequency and amplitude modulation, 8 improving mechanical quality factors, 9 in several parametric amplifications schemes, and in the implementation of mechanical logic. 10,11 Mode coupling may also be used in the enhancement of mechanically detected mass, charge, and force sensitivity. 12,13 For these reasons, such coupling has been studied in numerous top-down fabricated nanomechanical systems including single 14,15 and double beam structures 8,16 and membranes.…”

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“…The high structural quality of those materials combined with the reduced effective mass allows such beams to operate at very high resonance frequencies with extremely high Q factors (i.e., low damping). These beneficial attributes provide the basis for exceptional performance of MEMS applications such as extremely sensitive sensors [1][2][3][4], mechanical energy harvesters [5][6][7], nano/micro-relays [8,9], logic memory and computation [10][11][12], field effect transistors [13], and a high frequency reference in oscillators [14][15][16]. The MEMS devices implemented in these applications were mostly designed to operate in their linear resonant modes with the above-mentioned benefits.…”